Kauai Labs navX-MXP User Manual page 66

Guidance
Terminology
Y Forward/Backward
Z Up/Down
Because the gyroscope and accelerometer axes are aligned, navX-MXP measures linear
acceleration in the same set of 3 axes used to measure Pitch, Roll and Yaw. However unlike
Pitch, Roll and Yaw, acceleration measures linear motion rather than rotation, and is measured
in units of G, with a range of +/- 2.0.
Compass Heading
A compass measures the earth's magnetic field and indicates the current direction (heading)
relative to magnetic north (N). Compass Heading is measured in degrees and is similar to Yaw,
but has a few key differences:
Compass Heading has a range of 0-360 (where magnetic north is 0).
Compass Heading is absolute – it is referenced to magnetic north, and thus Compass
Heading does not drift over time
Important Note 1: Compass Heading relies upon being able to measure the earth's magnetic
field. Since the earth's magnetic field is weak, Compass Heading may not be able to measure
earth's magnetic field when the compass is near a strong magnetic field such as that generated
by a motor.
Important Note 2: Magnetic North is not exactly the same as True
calculate True North given a Magnetic North reading, as long as the current declination is
known. Declination is a measure of the difference in angle between Magnetic North and True
North, and changes depending upon your location on earth, and also changes over time at that
same location. An online calculator
earth location and date.
Altitude
+ Forward / – Backward
+ Up / – Down
is provided allowing one to calculate declination for a given
North. Your robot can
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